2.2.7.2 Size and Number of Disk Drives

Several sizes of disks are supported in multihost disk expansion units. Consider these points when deciding which size drives to use:

• If you use lower capacity drives, you can have more spindles; this increases potential I/O bandwidth, assuming the disks have the same I/O rates.

• If you use higher capacity disks, then fewer devices are required in the configuration. This can help speed up takeovers because takeover time can be partially dependent on the number of drives being taken over.

• You can determine the number of disks needed by dividing the total disk capacity that you have selected (including mirrors) by the disk size in your disk expansion units.